JPS643635B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a wrist drive device for a welding robot. In particular, the wrist drive device for a welding robot is capable of twisting and bending the wrist, which is supported by an arm and has a welding torch at the tip. This invention relates to a wrist drive device for a welding robot to provide a welding robot.

[Prior art]

FIG. 1 shows a conventional device, in which transmission shafts 4a and 4b are connected to drive parts 2a and 2b built into an arm 1 via universal joints 3a and 3b, respectively. A β ₀ gear 6a for giving bending to the wrist and a δ ₀ gear 6b for giving twist to the wrist are connected via universal joints 5a and 5b, and a wrist adapter 7 is connected to the tip of the arm 1. The wrist 8, which is movably supported, is driven. A welding torch 9 is supported at the tip of the wrist 8. A β ₁ gear and a δ ₁ gear (both not shown) that bend and twist the wrist 8 are meshed with the β ₀ gear 6a and the δ ₀ gear 6b. The wrist 8 bends (β) and twists (δ) as shown by the arrows by the driving force from the drive units 2a and 2b.

As described above, in the wrist drive device using gears, it is necessary to minimize the backlash between the gears in order to ensure the movement accuracy of the wrist 8. Conventionally, the β ₀ gear 6a, the δ ₀ gear The backlash was adjusted by rotationally adjusting the support members that support the respective bearings 6b.

However, such conventional means have the disadvantage that adjustment operations are difficult and workability is poor.

[Summary of the invention]

This invention was made in view of the above points, and the gear on the arm side, that is, the driving side, is supported by an eccentric cartridge supported by the arm, and the eccentric cartridge is operated from outside the arm to give rotational displacement. This provides a wrist drive device for a welding robot that can easily adjust the backlash between the main and driven gears.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2 to 5. δ ₀ gear 6 to which the driving force of the transmission shaft 4b is transmitted via the universal joint 5b
The gear shaft 10 of b is supported by an eccentric cartridge 13 via a sleeve 11 and a bearing 12, and the eccentric cartridge 13 is fitted and supported by the arm 1.

As shown in FIGS. 3 and 4, the eccentric cartridge 13 has a cylindrical shape with a bearing support hole 14 into which the bearing 12 is fitted, and a pair of left and right stepped portions 15a parallel to the central axis on the outer periphery. , 15b are formed, and in the cross-sectional shape of the eccentric cartridge 13, the outer circumferential circle and the bearing support hole 14 have an appropriate value e.
It has an eccentric structure.

Figure 5 shows the gear shaft 10, sleeve 11, and bearing 12.
The eccentric cartridge 13 is rotatably stored in the cylindrical storage hole 16 formed in the arm 1, and the eccentric cartridge 13 is rotatably stored in the cylindrical storage hole 16 formed in the arm 1. Insert the adjustment screw 1 into the screw holes 17a and 17b formed through the
8a and 18b, respectively, and adjust the adjustment screw 18.
The tips of a and 18b are brought into contact with step portions 15a and 15b, respectively. 19a and 19b are set screws.

With the above configuration, the set screws 19a, 19b
With the adjustment screws 18a and 18b removed, the adjustment screws 18a and 18b are rotated in opposite directions from the outside of the arm 1, thereby giving a rotational displacement to the eccentric cartridge 13.
Change the eccentricity e. In this case, the distance between the axes of the δ ₀ gear 6b and the δ ₁ gear 20b changes, so that the backlash between them is adjusted. Arrow A indicates an increase or decrease in backlash with respect to the direction of rotation of the eccentric cartridge 13. After adjustment, use the set screws 19a, 19b to tighten the adjustment screws 18a,
18b may be fixed.

The same applies to the backlash adjustment between the β ₀ gear 6a and the β ₁ gear 20a.

Note that the step portions 15a and 15b are not necessarily formed on the same plane, and may have an appropriate angle to each other.

〔Effect of the invention〕

As described above, the present invention is configured such that the gear shaft of the arm-side gear is supported by the eccentric cartridge rotatably stored and supported within the arm, and rotational displacement is applied to the eccentric cartridge from outside the arm. There is no need to disassemble the gear support part during assembly for adjustment, and the backlash can be easily adjusted after the arm and wrist are assembled, which has the effect of significantly improving the workability of robot assembly.

[Brief explanation of drawings]

Figure 1 is a schematic front view of the conventional device, Figures 2 to 5
The figures show one embodiment of the present invention, in which Fig. 2 is a front sectional view of the main part, Fig. 3 is a partially front sectional view, Fig. 4 is a sectional view taken along the - line in Fig. 3, and Fig. 4 is a sectional view taken along the - line in Fig. Figure 5 is the second
FIG. 3 is a cross-sectional view taken along the - line in the figure. 1... Arm, 2a, 2b... Drive section, 4a,
4b...Transmission shaft, 6a and 6b...β ₀ gear and δ ₀ gear (arm side gear), 8... Wrist, 10...
... Gear shaft, 11 ... Sleeve, 12 ... Bearing, 1
3...Eccentric cartridge, 14...Bearing support hole,
15a, 15b...Stepped portion, 16...Storage hole, 17
a, 17b...Screw hole, 18a, 18b...Adjustment screw (adjustment means), 19a, 19b...Set screw, 20a and 20b... _β1 gear and _δ1 gear (wrist side gear). In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A welding robot comprising an arm having a drive part, a wrist movably supported at the tip of the arm, and a gear housed in the arm and transmitting the driving force of the drive part to the wrist. In the wrist drive device, a pair of left and right stepped portions are formed on the outer periphery, eccentrically supporting a gear shaft of the gear on the arm side;
A cylindrical eccentric cartridge movably supported in a storage hole provided in the arm; and a cylindrical eccentric cartridge that is screwed into a pair of screw holes formed in the arm and engaged with the stepped portion to attach to the eccentric cartridge. a pair of adjustment screws that provide a rotational displacement and are fixed by a set screw, and the backlash of the gear is adjusted by adjusting the rotational position of the eccentric cartridge. Robot wrist drive device.